Back in April, under the auspices of a campaign titled No Meat No Heat, around a million people in Taiwan - including the speaker of parliament, the environment minister, and the mayors of Taipei and Kaohsiung - vowed to never again touch flesh nor fish. Given that Taiwan's Buddhist traditions mean around 1.2 million of its people are already vegetarian, this was perhaps not such a bold move as it seemed, but still: the organisers of the mass pledge cited the often overlooked contribution of livestock farming to greenhouse gas emissions, and presented it as an environmental move par excellence.

The decisive arrival of the current food crisis must be making them feel even more righteous. As daily news reports now remind us, there are three key factors behind the rocketing price of the most basic foodstuffs: the rising cost of oil, swathes of agricultural land being given over to biofuels, and the fact that the increasing affluence of China and India is spearheading an explosion in the demand for meat and the feed needed to produce it.

From there, it is only a small step towards an argument that is rapidly gaining ground: that with more than 850 million people going hungry, using huge amounts of water, grain, energy and land to rear livestock is a luxury now officially beyond us. This may suggest the arrogant west once again telling the rest of humanity to refrain from what we have happily done for years, but there is another way of thinking about it: à la the contraction and convergence model for tackling climate change, if we are to accommodate other countries' increased demand for meat, we will have to drastically reduce our own.

As the Alcoholics Anonymous mantra would have it: my name is John Harris and I am a vegetarian. I haven't eaten meat or fish since Christmas 1984, when I had my share of the Christmas turkey, and then quit. I can faintly recall arguments about the inbuilt inefficiencies of meat-eating, but the decision of this particular hard-bitten 14-year-old was based on two different considerations: first, a belief that it was wrong to kill sentient creatures to eat them; and second, that living without meat was an integral part of the 80s counterculture that set itself against the adult world, international capitalism, and Margaret Thatcher. With the arrival of the Smiths' album Meat Is Murder in 1985, everything became clear.

If only for reasons of space, we'll have to leave vegans out of this - but in the intervening 20-odd years, it's been strange to watch vegetarianism ooze so easily into the culture. The great post-PC backlash that began in the mid-1990s seemed to briefly threaten its quiet ascendancy - but though avowed British herbivores still form a pretty tiny minority (between 2% and 8% of us, according to polling), their influence is obvious. The recent story of British meat consumption may essentially be one of fish, chicken and processed meat supplanting our appetite for beef, pork and lamb straight from the butcher's block, but the parallel growth of vegetarian food has been astonishing: after well over a decade of year-on-year surges, the research firm Mintel reckons that the annual value of the British "meat-free" market is about to reach £780m.

In the midst of such progress, there has only been one drawback: the ongoing and inevitable association of vegetarianism with a very British piety (with the onset of age, one begins to understand Orwell's very reasonable distaste for the people he described as "vegetarians and communists"), and the mixed-up morals of the hardcore animal rights lobby. In 1999, I went to see Morrissey in concert, and heard him compare the meat industry's transgressions with slavery and the Nazi genocide; down the years, I've regularly confronted the assumption that refusing meat and fish somehow puts you in tight alliance with the people who seem to think that medical vivisection is a bigger problem than, say, human hunger.

Now, thankfully, there comes this new vegetarian(ish) agenda, and the chance to make the case against meat-eating on more level-headed grounds: that even if meat will remain part of most people's diet, they are going to have to eat less of it; and that right now, this is actually more about human lives than those of animals.

Newsnight recently ran an item on the arguments for cutting down, stuffed with the requisite statistics; for example, whereas it takes 20.9 square metres of land to produce 1kg of beef, to come up with the same weight of vegetables, the figure is 0.3 square metres. In the ensuing studio discussion, even the pro-meat contributor agreed that the world would now "have to value meat more highly", and Gavin Esler enthusiastically quizzed the vegetarian advocate, rather than trying to tear him to bits. By the end, one got the impression that they were discussing something almost unanswerable.

In the short-to-medium-term, it may well be the price of meat rather than high-minded ethics that sends sales of Quorn through the roof. Nonetheless, something is up: the possibility of a decisive sea-change that, back in the days of Smiths albums and endless lentils, would have been unimaginable. Millions of Britons following the Taiwanese and pledging en masse to go herbivorous may seem unlikely - but then again, I wouldn't rule it out.